There are three modes to the game, and choosing which to log into is your primary method of tailoring your game experience.
Open: Free-for-all deathmatch rules, for the most part. You might be killed by another player at anytime anywhere. Generally, if you're not in a heavily trafficked system, you probably won't see any players. Choose this if you want the greatest potential breadth of player interactions, both positive and negative.
Group: In this mode you only encounter players that are part of the group, allowing a great deal of ability to curate how many people you play with, or how those folks will behave. Nothing prevents them from acting contrary to the group's stated goals, but generally this is where you go if you want to play with people who are all on the same page. Small, self-curated groups are great for beating up the AI and hanging out with friends, larger ones can add a good bit of life to the game while minimizing (though, for emphasis, not eliminating) behavior that might by undesirable, such as player attacks and such, at least until the offending person is removed from the group.
Solo: It's you and the AI. If you just want to head out into space and live in the world without needing to, or worrying about, player interaction this mode guarantees it. You will, for better or worse as your preferences might dictate, never encounter a living player here. It's just you and the bots.